Dead PRAM battery

I would just replace the battery. It's quite easy to do. I took apart a handful of these eMacs and there are instructions available on the web with photographs.

I never heard of any issues running an OS X Mac with a dead PRAM battery. As long as you're using network time the PRAM battery will be for the most part obsolete. One of the very few advantages of OS X as a matter of fact.

However if you shall want to run OS 9 (booting to) please consider you might have nasty problems and it wont even start up.

In which case you should restart and press Cmd X
This will force your Mac to boot in X (providing both OS exists on the same volume)

Aside from losing any custom settings stored in PRAM ( What's stored in PRAM?), a dead PRAM battery will prevent some Mac models from starting up at all, especially if they've been unplugged for a lengthy period. I don't know how much time is "lenghty" for an eMac, but I'd say the potential hassle of a dead PRAM battery outweighs the minor cost and hassle of replacing the battery.

The PRAM battery will cost you somewhere around US$10 to $21 (figuring in tax and shipping) depending on whether bought online or at a local electronics store such as RadioShack. Instructions on replacing the battery are available at eMac - Do-It-Yourself.

Hi Kiraly,

My PRAM battery is dead

Technically the term for this battery is "logic board battery" and while it does retain date and time settings it also runs the PMU which is responsible for power management. Probably still the PMU99 chip. This is from the service manual for your 1.25 (first one):
"If the computer has a “No Power” situation, check the battery before replacing modules. A
drained battery may be indicative of a crashed Power Management Unit.
With the battery in the battery holder (under load), measure the voltage across the battery’s positive and ground terminals.
Does the battery measure at least +3.5v? If not, replace the battery and reset the PMU. If the battery does measure over +3.5v, reinstall the battery and reset the PMU as above"

I would just replace it as Foxberg and JMVP have already said. It's $4.99 (cheapest price - RS is outrageous) here at OWC plus shipping, $3 to me but I'm just across town:
http://eshop.macsales.com/item/Newer%20Technology/BAA36VPRAM/
Also it's dead simple as they have said. With the access door off it's right there.

Richard

I would not worry about it. I have a eMac (1st Generation) myself with a dead battery and it causes no problems as long as there is a constant power source, network time on in OS 9 & X along with a internet connection, it works for me, and its been dead for 3 years. Same with my (sadly) Flower Power iMac.

Hey Guys!
I know what to do! go here http://eshop.macsales.com/item/Newer%20Technology/BAA36VPRAM/
Have a good one!

Matthew Knice